Geometrical and structural aspects of concrete fracture

✍ Scribed by Jan G.M Van Mier; M.B Nooru-Mohamed

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 75 KB
• Volume: 35
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(90)90235-9

✦ Synopsis

Results

are presented of uniaxial and biaxial tensile experiments. Relatively large specimens were chosen to study the fracture mechanism of concrete. Essentially the material experiments were regarded as structural tests, from which material properties must be derived, by either varying the boundary conditions or the specimen geometry. In the present paper the specimen shape was varied: SEN and DEN geometries were studied under uniform boundary displacement. Structural changes were determined utilizing detailed surface deformation measurements and a photoelastic technique. The results suggest that two basic mechanisms take place in the softening regime of concrete. Firstly, the development of discrete perimeter cracks along the circumference of the specimen leading to a steep stress-drop in the softening regime just beyond peak, and secondly bending of intact ligaments between the perimeter cracks leading to large deformations in the softening zone. The first mechanism is largely influenced by possible stress-redistributions that may occur within the specimen. The mechanism is used for explaining the response of DEN specimens under biaxial tensile loads.